infectiousYawn

i gave that a shot and it didnt work. ive done virus scans and everything and i cant seem to find out what the problem is :

Greetings, I just bought my system a few weeks ago. Everything up until this morning was working just fine. I went to watch tv using MC and it was black for a second and then it went back to my desktop. I tried it again and the same thing. So I used the remote to activate the main MC screen and it starts off normal and then a few seconds later it just closes and im back to my desktop. It doesnt even say anything has crashed or anything. Ive tried system restore to a few days ago when I know it worked and nothing. Anyone have any ideas as to what the problem might be?